import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;

/**
 * Created by dell on 2017/8/11.
 */
public class HashTest {
    public static void main(String[] args) {
        Map map=new HashMap();
        map.put("111",111);
        map.put("222","222");
        map.put(null,"333");
        map.put("456","567");
        //map.put("111","222");
        //map.remove("111");
        System.out.println(map);
        Hashtable tab=new Hashtable();
       // tab.put(null,"2");
        System.out.println(tab);
    }
}
